Sex ratio is not the stock market

By Chiang Sheng 江盛

The department is behaving like Miguel de Cervantes’ Don Quixote, riding around on a skinny old horse, accompanied by his faithful but not very bright retainer, and challenging windmills that he imagines to be giants.

There is plenty of data available about sex ratios, and many studies prove that the ratio tends to fluctuate. It is affected by environmental, social and economic factors, and by climate, temperature, latitude and environmental pollution. Further variables include the ethnicity of the mother, whether she has given birth previously and the length of her pregnancy.

Historical sex ratios at birth for developed countries that do not allow gender selection are mostly between 1.03 and 1.08, so if the sex ratio falls between these two figures, it ought to be considered normal.

In Taiwan, reproductive technology and economic prosperity have at times led to a relatively high proportion of male babies. The sex ratio following the introduction of reproductive technology rose to 1.14. Over the last two decades, the male-to-female ratio for first and second babies has remained steady, but there have been variations in the ratio for the third baby and above.

There is also a connection between this and the economic cycle. For example, during the 2008 global economic crisis and the 1990 economic contraction, the sex ratio started to fall from previous peaks.

If 1.08 is a figure that experts find acceptable for sex ratio at birth, why is the department getting so flustered about what is evidently a bogus issue?

The department should avoid reacting to fluctuations in the sex ratio figures as if it were a patient suffering from anxiety, paranoia, obsessive-compulsive disorder or panic attacks; otherwise, its pronouncements, policymaking and implementation will all be out of tune with reality.

Last week, the department came up with yet another policy, announcing a ban on genetic testing of maternal blood, but then it changed its tune again, saying that the ban only applied to screening for sex-linked hereditary illnesses and not for Down syndrome.

This shows that the department has only a half-baked scientific and ethical understanding of pre-birth non-invasive chromosomal evaluation.

As always, its policies are highly populist, but thoroughly unconvincing.

Chiang Sheng is an attending physician in the Department of Obstetrics and Gynecology at Mackay Memorial Hospital.